Question: Is wireless ready for control?
Answer: The IEC 62591 (WirelessHART) standard was designed for both control and monitoring from the very beginning. However, users wanted four key pillars in place before putting theory into action. Proof of comprehensive wireless system security, redundant systems, faster device scan rates and proven field experience were required before users considered wireless to be “ready” for control.
In the coming months, the market will see the release of devices with faster scan rates, integrated wireless system I/O cards and redundant gateways. WirelessHart networks have achieved FIPS and Achilles certifications for data encryption and network security. Before using wireless for control, the biggest need for manufacturers was getting true field experience to see how the IEC-approved WirelessHart standard really worked. With over 1,400 sites around the world and over 200 million hours in operation, WirelessHart networks have proven to be reliable and robust enough for control.
Wireless networks are inherently easier and more cost-effective to implement than traditional, wired control solutions due to fewer components. The ease of adding measurements for control can save as much as 60% on installation time. Today we’ve seen users implementing wireless in control applications that are inherently troublesome for wired architectures. For chemical sites, applications with high temperatures, long wire runs in environments with high electromagnetic interference (EMI), remote locations, or mobile skids are examples where installing traditional wired control is often cost-prohibitive and often not technically possible. Temperature, level and steam-flow control applications are also good candidates for wireless control. Replacing manual control or adding wireless secondary control can reduce energy usage and risks for safety or environmental incidents.
It’s just a matter of time before wireless for control applications become mainstream — just as cell phones have replaced wired lines for most telephone uses. There will likely still be applications that will remain wired, but may have wireless monitoring or control as the secondary safety systems. Today, WirelessHart systems are being used for basic control applications with proven results and reliability.
Bob Karschnia is vice president, wireless for Emerson Process Management
(Chanhassen, Minn.; www.emersonprocess.com)